Add automated test for "Search for a page without locale"

The manual test is here: Search for a page without locale

Existing automated coverage

• SearchSuggestIT#verifySearchSuggestTitles: Step 4 and the expected result for a page saved through REST: searching its title in the search bar lists it in 'Page titles'

Missing automated coverage

• As Admin, run the Velocity snippet that does $xwiki.getDocument('SomeSpace.SomePage'), setTitle('Foobar') and save() (e.g. from a page in wiki syntax)
• Assert the page exists at SomeSpace.SomePage with the title 'Foobar'
• Wait for the Solr queue, search 'Foobar' in the search bar and assert SomeSpace.SomePage is listed in the 'Page titles' section

Suggested location: xwiki-platform-core/xwiki-platform-search/xwiki-platform-search-test/xwiki-platform-search-test-docker/src/test/it/org/xwiki/search/test/ui/SearchSuggestIT.java

Found by comparing the XWiki 18.4.4 manual test runs against the automated tests on master (a0055f10a1a).